Effect of Photorefractive Keratectomy Using Three Methods in Myopic Eyes with Astigmatism <1.00 D

Document Type : Original article

Authors

1 OD in Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran

2 Student Research Committee, MSc in Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran

3 Associate Professor of Ophthalmology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

4 MSc in Biostatistics, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Abstract

Background and Aims: To compare the results of Photorefractive Keratectomy (PRK), surgery was performed using three Conventional, Iris Registration, and Spherical Equivalent methods in correcting astigmatism Materials and Methods: In the current cohort study, 72 myopic eyes (40 patients) with astigmatism less than 1.00 D were randomly divided into 3 groups (Conventional, Iris Registration, and Spherical Equivalent) and were respectively reviewed. In the first group, the excimer laser changed the corneal curvature regardless of the rotation of the eye. In the second group, a high resolution photo of the iris was provided before surgery and the amount of rotation of the eye in the lying state was measured related to the sitting. Finally, in the last group, half of power of the cylinder was added to the sphere and regardless of the rotation and axis of cylinder, the surgery was performed. Residual astigmatism and outcomes were compared with initial data six months postoperatively.
Results: The mean age of patients was 28.19±5.35. Preoperative BCVA was 10/10 in all patients. No statistical difference was noticed between the groups (p>0.05) in the preoperative astigmatism. In Conventional PRK group, the average astigmatism decreased from-0.48±0.30 D preoperatively to -0.19±0.20D postoperatively (p=0.002) and the average astigmatism in Iris Registration PRK group decreased from -0.54±0.19D preoperatively to -0.18±0.21D postoperatively (P<0.001), compared with the increased astigmatism in Spherical Equivalent PRK group from -0.55±0.12D preoperatively to -0.65±0.16D postoperatively (p=0.008). The average myopia decreased from -3.90±1.04 to 0.04±0.35D in Conventional group, decreased from -3.77±1.04 to 0.44±0.35 in Iris Registration group, and decreased from -2.58±1.11 to 0.14±0.28 in Spherical Equivalent group.
Conclusion: According to the results, Conventional and Iris Registration PRK decreased the amount of postoperative astigmatism more than Spherical Equivalent PRK. The amount of postoperative myopia decreased in the three groups.

Keywords

Main Subjects

References

1. Dandona R, Dandona L. Refractive error blindness. Bull World Health Organ2001;79:237-243.##
2 .Sach G. Astigmatismes, videokeratoscopie et lentilles de contact: apportd'une nouvelle geometrie "a degagement inverse" pour les cornees irregulieres. Visions Internationales.1993; 40: 14-25. ##
3.Colette Gallinaro, MD, Pierre Jean Toulemont, MD et all . Excimer laser photorefractive keratectomy to correct astigmatism . J Cataract Refract Surg 1996; 22:557-563##
4. Attebo K, Mitchell P, Smith W. Visual acuity and the causes of visual loss in Australia. Ophthalmology. 1996;103:357-364. ##
5.Read SA, Collins MJ, Carney LG. A review of astigmatism and its possible genesis. Clin Exp Optom 2007;90:5-19. ##
6. Yekta A, Fotouhi A, Hashemi H, et al. Prevalence of refractive errors among schoolchildren in Shiraz, Iran.
Clin Experiment Ophthalmol 2010;38:242-248. ##
7. Bores LD, Myers W, Cowden J. Radial keratotomy: an analysis of the American experience. Ann Ophthalmol. 1981; 13:941-948. ##
8. Ellis W. A Textbook of Radial Keratotomy and Astigmatic Surgery. Irvine, CA, KC Terry, 1986. ##
9.Fenzl RE. Control of astigmatism using corneal incisions. In: Sanders DR, Hofmann RF, eds, Refractive Surgery: A Text of Radial Keratotomy. Thorofare, NJ, Slack Inc, 1985; 151-166. ##
10. Fyodorov SN, Durnev VV. Surgical correction of complicated myopic astigmatism by dissection of circular ligament of cornea. Ann Ophthalmol.1981; 13:115-118. ##
11. Goes FJ. Photorefractive keratectomy for myopia of –8.00 to –24.00 diopters. J Refract Surg. 1996;12:91–97. ##
12. Hersh PS, Schein OD, Steinert R. Characteristics influencing outcomes of excimer laser photorefractive keratectomy. Summit Photorefractive Keratectomy Phase II Study Group Ophthalmology. 1996;103:1962–1969. ##
13. Onclinx T, Smith RJ, Maloney RK. Induced astigmatism after photorefractive keratectomy. J Cataract Refract Surg. 1999;25: 183–187. ##
14.Lowenstein A, Lipshitz I, Lichtenstein F, Ben-Sirah A, Lazar M. The effect of spherical photorefractive keratectomy on myopic astigmatism. J Refract Surg. 1995;11 Suppl 3:S263–S264##
15. Steven M Christiansen , Mark D Mifflin , et al . Astigmatism induced by conventional spherical ablation after PRK and LASIK in myopia with astigmatism
16. Tabin GC, Alpins N, Aldred GF, et a!.Astigmatic change 1 year after excimer laser treatment of myopia and myopic astigmatism. J Cataract Refract Surg. 1996; 22:924-930. ##
17.Bailey MD, Mitchell GL, Dhaliwal DK, Boxer Wachler BS, Zadnik K. Patient satisfaction and visual symptoms after laser in situ keratomileusis. Ophthalmology 2003; 110:1371–1378. ##
18.Marcos S. Aberrations and visual performance following standard laser vision correction. J Refract Surg 2001; 17:S596–S601. ##
19.Mrochen M, Kaemmerer M, Mierdel P, Seiler T. Increased higher-order optical aberrations after laser refractive surgery; a problem of subclinical decentration. J Cataract Refract Surg2001; 27:362–369. ##
20.Moreno-Barriuso E, MerayoLloves J, Marcos S, Navarro R, Llorente L, Barbero S. Ocular aberrations before and after myopic corneal refractive surgery: LASIK-induced changes with laser ray tracing. Invest Ophthalmol Vis Sci 2001; measured42:1396–1403. Available at: http://www.iovs.org/cgi/reprint/42/6/1396. Accessed December 31, 2009. ##
21. El-Maghraby A, Salah T,Waring GO 3rd, Klyce S, Ibrahim O.Randomized bilateral comparison of excimer laser in situ keratomileusis and photorefractive keratectomy for 2.50 to 8.00 diopters of myopia.ophthalmology
1999;106(3):447-457. ##
22. Gimbel HV, Anderson Penno EE, van Westenbrugge JA, Ferensowicz M, Furlong MT. Incidence and management of intraoperative and early postoperative complications in 1000 consecutive laser in situ keratomileusis cases. Ophthalmology 1998;105(10):1839-1847. ##
23. Seiler T, Kaemmerer M , et al .Ocular Optical Abberation After Photorefractive Keratectomy for Myopia and Myopic Astigmatism .Arch Ophthalmol.2000;118:17-21. ##
24.Colin J , Cochener B , et al . Excimer Laser Treatment of Myopic Astigmatism . Ophthalmology.1998;105:1182­-1188. ##
25. Niles Charles, MD, Culp Bonnie, RN, Teal Patricia, MD. Excimer laser photo refractive keratectomy using an erodible mask to treat myopic astigmatism , J Cataract Refract Surg. 1996; 22:436-440. ##
26. Moshirfar Majid, MD, Schliesser Joshua A,Chang Joann C , et al. Visual outcomes after wavefront-guided photorefractive keratectomy and wavefront-guided laser in situ keratomileusis: Prospective comparison. J Cataract Refract Surg. 2010; 36:1336–1343. ##
The Scientific Journal of Rehabilitation Medicine
Volume 7, Issue 3
September and October 2018
Pages 217-225

Files

History

  • Receive Date: 16 September 2017
  • Revise Date: 07 January 2018
  • Accept Date: 17 January 2018
  • First Publish Date: 23 September 2018

Share

How to cite

Statistics